Shunt Compensator

1. Statcom
Yohan Fajar Sidik, S.T.
Johan Agung Irawan, S.T.
UGM, 17 Oktober 2012

2. Introduction
Source: http://www.alstom.com/grid/products-and-services/engineered-energy-
solutions/flexible-ac-transmission-system/

3. Shunt Compensation
Statcom: compensation devices
P=0
It serves of link Current is in quadrature Vs
DC voltage for VSC  DC capacitor

4. Statcom: GTO and Controller
High side voltage
is used as a Less harmonics,
controller input Require minimal or no harmonic filter
GTO
Multi stage converter

5. Equivalent Circuit
Variable ac voltage
Transformer leakage inductance

6. Principle Operation
Vi = Vs  No current or reactive
Vi > Vs  reactive will be sent
Vi < Vs  reactive will be absorbed

7. V-I Characteristic of a STATCOM
• If the system voltage exceeds V1 or V2,
STATCOM acts as a constant current source by
controlling the converter voltage (Vi)
appropriately.

8. The STATCOM Advantages
• Quicker response time
• Active power control is possible (with optional
energy storage)
• No potential for creating a resonance point (no
required capacitor banks or reactors )
• Has a smaller installation (no required capacitor
banks or reactors , high capacity power
semiconductor devices)
• Allows for high availability (one/more STATCOM
modules can be off without lossing the entire
compensation system)

9. Application in Voltage Stability
• One of the major causes of voltage instability
is the reactive power limit of the system.
• Series and shunt compensation can increase
the maximum power network transfer
capabilities, inject reactive power to maintain
the voltage magnitude.
• FACTS (ex:STATCOM) can adjust the voltage
magnitude in some node of the system.

10. The Three-Phase STATCOM Model

11. Reference
• http://www.icrepq.com
• http://www.donsion.org/calidad/cc8/c8-11.pdf
• http://www.donsion.org/investigacion/trabajos/f
acts-EMC2007.pdf
• http://www.meppi.com/products/facts/documen
ts/facts%20and%20custom%20power%20equipm
ent%20for%20the%20enhancement%20of%20po
wer%20transmission%20system%20performance
%20and%20power%20quality.pdf